Field of the Invention
The present invention relates to data storage devices with flash memory and flash memory control methods.
Description of the Related Art
Flash memory, a data storage medium, is common in today's data storage devices. For example, flash memory is typically used in memory cards, USB flash devices, solid-state drives, and so on. In another application with multi-chip package technology, a NAND flash chip and a controller chip are combined in one package as an embedded multi-media card (e.g. eMMC).
A flash memory device provides storage space which is divided into blocks, and each block includes a plurality of pages. An erase operation designed for flash memory is performed on a block-by-block basis, to release space one block at a time. When updating data, the new data is written into a spare space rather than being overwritten on old data. To manage the flash memory, the mapping information between the host side and the flash memory has to be maintained. It is more complex to manage flash memory rather than other conventional storage mediums. It can be very tricky to manage mapping information for a flash memory.